Oswalt pitched eight superb innings, Jimmy Rollins drove in four runs and the Philadelphia Phillies beat the San Francisco Giants 6-1 Sunday night to even the NL championship series at one game apiece.

“I’m hoping for a momentum switch and get back to San Francisco and take the series there,” Oswalt said.

The series shifts to San Francisco for Game 3 on Tuesday afternoon. Matt Cain faces Philadelphia’s Cole Hamels, the 2008 World Series MVP.

Even though he didn’t finish the outing, it sure was a complete game for Oswalt. He allowed one run and three hits, striking out nine. He also singled using one of Rollins’ bats and scored a run after racing through a coach’s stop sign in the seventh.

Instead of his pitching, everyone wanted to know what he was thinking on the bases.

“First thing in my mind was score,” Oswalt said. “When I got halfway, I saw the stop sign. I said it’s too late now. No turning back.”

Rollins kidded Oswalt about it.

“It was a nice slide,” he said. “That was something I would do. Actually, I probably wouldn’t have needed to slide.”

Cody Ross hit his third solo homer in two games for the Giants, who struck out 10 times.

Rollins busted out of a 1-for-15 postseason slump, going 2 for 3 with a bases-loaded walk and a bases-clearing double.

“I knew it was just a matter of time,” Rollins said.

Halladay followed up his no-hitter against the Reds in the division series with a subpar performance in Game 1. He gave up four runs in seven innings.

But Oswalt showed why the Phillies got him from Houston before the trade deadline, shutting down the Giants in a crucial spot.

“You can’t get caught up in the moment of trying to get momentum back on your side,” Oswalt said. “You have to pitch your game.”

Sanchez gave up three runs — two earned — and five hits in six-plus innings. The tough lefty had dominated the Phillies in his five previous starts against them, not allowing more than four hits in any outing.

Oswalt chased Sanchez with a line-drive single leading off the bottom of the seventh. He advanced to second on Shane Victorino’s sacrifice off Ramon Ramirez. After Chase Utley was intentionally walked, Placido Polanco lined a single to center. Oswalt ran through third-base coach Sam Perlozzo’s stop sign and slid safely ahead of the relay throw to give the Phillies a 3-1 lead.

“That was comical,” Rollins said. “Roy’s got those stiff hips and he looked like he was cardboard running down the line but he got it done tonight.”

Jeremy Affeldt came in and struck out Ryan Howard after a double steal. Jayson Werth was intentionally walked before Santiago Casilla entered to face Rollins. The former NL MVP, dropped from leadoff to sixth in the batting order since the playoffs started, hit a drive off the right-center field fence to put the Phillies up 6-1.

An appreciative crowd chanted “J-Roll! J-Roll!” with a smiling Rollins standing on second.

“I got a lot of faith in him,” manager Charlie Manuel said. “I know how much he wants to be up there.”

Oswalt didn’t allow a hit until Ross connected with one out in the fifth to tie it at 1. He ripped a 1-0 pitch into the left-center field seats — nearly the same spot both of his homers off Halladay landed.

But the Phillies played small-ball — a rarity for this lineup filled with inconsistent sluggers — to take a 2-1 lead in the bottom half.

Victorino, one of the few Phillies with success off Sanchez, lined a double down the left-field line. He advanced to third on Utley’s fly out to right and scored on Polanco’s sacrifice fly to center, which drew a loud ovation.

The Phillies took advantage of Sanchez’s wildness and scored an unearned run without getting a hit in the first.

Utley, flip-flopped with Polanco in the batting order, drew a one-out walk. Utley stole second and advanced to third when Polanco reached on third baseman Mike Fontenot’s throwing error. Howard worked a walk after falling behind 1-2 in the count.

Sanchez then caught Werth looking at a slider for the second out. But Rollins walked to force in a run. Raul Ibanez fanned to end the inning.

Rollins got his second hit of the playoffs in the fourth when Fontenot let his popup land untouched near the mound.

Acquired from Houston on July 29, Oswalt went 7-1 with a 1.74 ERA in 13 games with the Phillies. Oswalt — not Halladay or Hamels — was Philadelphia’s best pitcher down the stretch. The three-time All-Star was 7-0 with a 1.17 ERA in his last 10 starts.

Oswalt struggled against Cincinnati in Game 2 of the division series. He gave up three earned runs in five innings in a 7-4 win.

The Giants saw a different version of Oswalt.

“He threw really great,” Giants manager Bruce Bochy said. “He was on and he had his stuff.”

For the third straight postseason, the city hosted a day-night football-baseball doubleheader with the Eagles playing early. The sports complex had a Christmas feel as fans wore their green and red to support both teams.

Just like the last two years, the Eagles did their part. They beat Atlanta 31-17. In ‘08, it was a city sweep with the Phillies beating Tampa Bay in Game 4 of the World Series in the nightcap after an Eagles’ win over the Falcons. Last year, after the Eagles beat the New York Giants, the Phillies lost to the New York Yankees in Game 4 of the World Series.

The crowd of 46,099 — the 135th straight sellout at Citizens Bank Park — was revved up right from the start, waving their “Fightin’ Phils” rally towels and chanting “Let’s Go Phillies.”

They cheered loudly when Oswalt brushed back Ross with a high-and-tight fastball in the second.

Notes: Howard spent part of his day watching the Eagles on the field in one end zone. He led a cheer and then hitched a ride with the Phillie Fanatic, riding on the back of the furry green mascot’s four-wheeler to get to the ballpark. ... Former Phillies outfielder and current broadcaster Gary Matthews, the 1983 NLCS MVP, threw out the first pitch. ... Sanchez beat the Phillies twice in the regular season, allowing just two runs in 13 innings. He’s 3-1 with a 2.48 ERA against them in the regular season, losing 1-0 for his only defeat. ... Giants leadoff hitter Andres Torres struck out swinging four times.